The purpose of this project is to map the locations at which specific genes are expressed in pre-implantation mouse embryos. Dr. Minoru Ko's group in LG has used expression profiling with microarrays to identify 500-1000 genes that are differentially expressed at various stages of early mouse embryo development. Dr. Yoshikawa was successful at developing medium-throughput techniques for processing whole-mount embryos for in situ hybridization and microscopy. He was able to apply these techniques to map the locations of 91 candidate genes that were transcription factors highly expressed in blastocysts. Of these 91, 48 were found to be expressed predominantly in the inner-cell mass. The expression of these genes predominantly in the ICM suggests their importance in maintaining pluripotency. This project is now split into separate projects at the Developmental Genomics and Aging Section (DGAS) and the Image informatics and Computational Biology Unit (IICBU). Within the IICBU, the continuation of this project (Development And Applications Of The Open Microscopy Environment) involves establishing the informatics infrastructure for a publicly accessible repository of in-situ hybridization images as well as the development of tools to annotate and analyze these images. Within DGAS, continuation of this project involves assaying spatial distribution of expression patterns of selected developmental genes in the early mouse embryo and embryonic stem cells.